validation

This module provides helpers for patterns regarding validateRequest, willValidate and

didValidate events.

Validation messages can have one of the following structures:

• A simple i18n html message object (locale to html string mapping). It will get a default level of #LEVEL_ERROR.
• A message object as required by the messages widget consisting of an i18n html message object under the key i18nHtmlMessage and a level under the key level.

Contents

Module Members

• LEVEL_SUCCESS
• LEVEL_INFO
• LEVEL_WARNING
• LEVEL_ERROR
• successEvent()
• errorEvent()
• handlerFor()

Types

• ValidationHandler
  • ValidationHandler.registerResourceFromFeature()
  • ValidationHandler.registerResource()

Module Members

LEVEL_SUCCESS String

Constant for the value "SUCCESS", indicating a successful validation outcome.

LEVEL_INFO String

Constant for the value "INFO", indicating a validation outcome with informational messages.

LEVEL_WARNING String

Constant for the value "WARNING", indicating a validation outcome with warnings.

LEVEL_ERROR String

Constant for the value "ERROR", indicating an erroneous validation outcome.

successEvent( resource, messages )

Creates and returns an event resembling a successful validation result.

Parameters

Returns

errorEvent( resource, messages )

Creates and returns an event resembling the result of a validation with errors.

Parameters

Returns

handlerFor( context, configuration )

Creates and returns a new handler for validateRequest events for a given context. It handles sending of willValidate and didValidate events, including the output of the given validator function.

Parameters

Returns

Types

ValidationHandler

ValidationHandler.registerResourceFromFeature( featurePath, validator, optionalOptions )

Registers a validator for validateRequest events for a resource configured under the given feature. It is assumed that the given feature has a resource property with the name of the resource to validate. If the property is not found, an assertion will fail. If on the other hand the option isOptional is given as true, this is ignored and nothing good or bad happens.

Apart from that this function works just like #ValidationHandler.registerResource.

Example: Consider the following configuration for a widget:

{
   "features": {
      "amount": {
         "resource": "theAmount"
      }
   }
}

An example using that would be:

validation.handlerFor( context )
   .registerResourceFromFeature( 'amount', ( event, meta ) => {
      if( isAmountValid() ) {
         return null;
      }
      return 'The given amount is not valid';
   } );

Parameters

Returns

ValidationHandler.registerResource( resource, validator )

Registers a validator for validateRequest events for the given resource.

The validator must be a function, that handles the actual validation necessary for the resource. The validation result is always signaled through one or more generated error messages or the absence of these messages. So valid results may be a string, an i18n object, an array of the former, null or an empty array. null and an empty array signal a successful validation.

The validator receives the event object for the validateRequest event and its according meta object.

The way these messages are returned by the validator may be one of two ways, depending on the nature of the validation:

• if the validation can be handled synchronously, the result should simply be returned directly
• in case the validation is asynchronous, a promise must be returned, which must be resolved with the same kind of values as for the synchronous case

If the validator throws an error or the promise is rejected, this is treated as a failed validation. Since this is due to a programming error, the error or rejection cause will be logged and a configurable message will instead be send in the didValidate event. The message is assumed to be found in the global configuration at lib.laxar-patterns.validation.i18nHtmlExceptionMessage as string or i18n object. If it cannot be found, an empty string is send as message.

Example:

validation.handlerFor( context, configuration, log, i18n )
   .registerResource( 'theAmount', ( event, meta ) => {
      return context.resources.theAmount > 1000;
   } )
   .registerResource( 'currentUser', ( event, meta ) => {
      return fetchUserValidityRules()
         .then( rules => context.resources.currentUser.meets( rules ) )
         .then( valid => {
            return valid ? null : 'The current user isn\'t valid for some reason. Do something!';
         } );
   } );

Parameters

Returns